Electronic devices, such as palm computers, digital cameras and cellular telephones, are becoming more compact and miniature, even as they incorporate more sophisticated data processing and storage circuitry. Moreover, types of digital communication other than text are becoming much more common, such as video, audio and graphics, often using massive amounts of data to convey the complex information inherent therein. These developments have created an enormous demand for new storage technologies that are capable of handling enormous amounts of data at a lower cost and in a much more compact package.
There is a continued need for increased miniaturization and expanded ability to handle greater quantities of data at a faster speed and in even more compact areas. The industry is moving towards the storage of data having a cell size in the range of tens to hundreds of nanometers.
In some storage devices, such as CD-RW and DVD-RW drives, data is written and/or detected using directed light beams, such as lasers, to reversibly change the optical reflectivity of a storage medium. As data storage densities and miniaturization increase, the diffraction-limited spot size of the lasers sets a lower bound to the size of bits to be written. Thus, optical storage is limited by the wavelength of the directed light beam.
The storage of data at substantially increased densities gives rise to problems in the task of reading the data. High-density storage devices make sensing data increasingly difficult because of interference from neighboring non-selected memory cells and because the flows of electrons, photons or holes generated from the sensing process are so small that detection becomes extremely difficult and errors in data detection increase.
Accordingly, to read miniature data cells in high-density memory storage, it is desirable to develop techniques capable of producing greater amounts of carrier flows and more effective methods of converting energy from probe electrons to detectable carriers. Memory structures and methods are needed to store and read high-density data so that detection of data is more readily obtained.
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.